libcxx_old/test/std/containers/unord/unord.set/rehash.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <unordered_set>

// template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
//           class Alloc = allocator<Value>>
// class unordered_set

// void rehash(size_type n);

#include <unordered_set>
#include <cassert>

#include "test_macros.h"
#include "min_allocator.h"

template <class C>
void rehash_postcondition(const C& c, size_t n)
{
    assert(c.bucket_count() >= c.size() / c.max_load_factor() && c.bucket_count() >= n);
}

template <class C>
void test(const C& c)
{
    assert(c.size() == 4);
    assert(c.count(1) == 1);
    assert(c.count(2) == 1);
    assert(c.count(3) == 1);
    assert(c.count(4) == 1);
}

int main(int, char**)
{
    {
        typedef std::unordered_set<int> C;
        typedef int P;
        P a[] =
        {
            P(1),
            P(2),
            P(3),
            P(4),
            P(1),
            P(2)
        };
        C c(a, a + sizeof(a)/sizeof(a[0]));
        test(c);
        assert(c.bucket_count() >= 5);
        c.rehash(3);
        rehash_postcondition(c, 3);
        LIBCPP_ASSERT(c.bucket_count() == 5);
        test(c);
        c.max_load_factor(2);
        c.rehash(3);
        rehash_postcondition(c, 3);
        LIBCPP_ASSERT(c.bucket_count() == 3);
        test(c);
        c.rehash(31);
        rehash_postcondition(c, 31);
        LIBCPP_ASSERT(c.bucket_count() == 31);
        test(c);
    }
#if TEST_STD_VER >= 11
    {
        typedef std::unordered_set<int, std::hash<int>,
                                      std::equal_to<int>, min_allocator<int>> C;
        typedef int P;
        P a[] =
        {
            P(1),
            P(2),
            P(3),
            P(4),
            P(1),
            P(2)
        };
        C c(a, a + sizeof(a)/sizeof(a[0]));
        test(c);
        assert(c.bucket_count() >= 5);
        c.rehash(3);
        rehash_postcondition(c, 3);
        LIBCPP_ASSERT(c.bucket_count() == 5);
        test(c);
        c.max_load_factor(2);
        c.rehash(3);
        rehash_postcondition(c, 3);
        LIBCPP_ASSERT(c.bucket_count() == 3);
        test(c);
        c.rehash(31);
        rehash_postcondition(c, 31);
        LIBCPP_ASSERT(c.bucket_count() == 31);
        test(c);
    }
#endif

  return 0;
}